1. Field of the Invention
The invention relates to a liquid-droplet ejection head for ejecting liquid droplets onto the recording medium and an ink jet printer including the liquid-droplet ejection head.
2. Description of the Related Art
A known ink jet head for ejecting ink droplets includes a channel unit in which a common ink chamber and a plurality of individual ink channels are formed. The common ink chamber includes a plurality of manifold channels. The individual ink channels extend from exits from the manifold channels through pressure chambers to nozzles. The channel unit has a laminated structure in which a plurality of plates are stacked. Among these plates, manifold plates defining the side walls of the manifold channels include island-shaped partial plates surrounded by the manifold channels. The partial plates transverse the manifold channels and are supported by rectangular support portions connected to the opposite side walls of the manifold channels.
In the above-described ink jet head, bubbles flowing into the manifold channels stick to the side edges of the support portions and tend to stay in the manifold channels. Because the side edges of the support portions are perpendicular to a direction in which the manifold channels extend, i.e., a direction in which ink flows. As a result, a large amount of ink has to be discharged to discharge the bubbles outside, resulting in unnecessary consumption of ink.